Secondary and miscellaneous urolithiasis. Medications, urinary diversions, and foreign bodies.

Secondary stones, those with no "classic" cause, provide unusual diagnostic and treatment challenges to the urologist. Stones related to medications, to urinary diversions or augmentation, or to presence of foreign bodies within the urinary tract occur rarely. Nevertheless, they represent situations that may be corrected fully by appropriate conservative or procedural therapy, and therefore they must be included in the differential diagnosis of many patients who present with symptoms of urolithiasis.